Targa Miata
October 24, 2009 - While I had the fuel rail off, I decided to swap injectors.
I had been using stock 1999-00 injectors (the red one) and I had a set of 2001-05 injectors (purple) on the shelf. The reds are 240cc and the purples are 265.
Why? Because I've come to realize that I simply may not have had enough injector in the car and that might have been causing the car to run lean at sea level. When I drop down to sea level from 5000', the engine makes 20% more power because of the thicker air. Could this be why the car was wanting to detonate at Laguna Seca, or why it started to misfire on the last day of the Targa? I don't know, but quite possibly. It should have been a fairly easy thing to do and Jeremy at FM mentioned it to me once a couple of years back. Between one thing and another, it just never got done.
I'll be more comfortable with the larger injectors. Also, I'll get more fuel from the higher pressure. Will these 270s be enough? Not if I start to get close to 200 hp, that's about where they peak. In that case, I have a set of 550cc injectors I can swap in. But they'd require new connectors for the injectors so I didn't bother to do that. I'm about to embark on a series of tests and I'd like to leave the wiring as unmolested as possible for the time being.
entry 711 - tags: fuel pressure, injectors